National Socio-Environmental Synthesis Center, University of Maryland, Annapolis, MD 21401;
Department of Ecology and Evolutionary Biology and National Institute for Mathematical and Biological Synthesis, University of Tennessee, Knoxville, TN 37996.
Proc Natl Acad Sci U S A. 2021 Jan 26;118(4). doi: 10.1073/pnas.2010121118.
Global cropland expansion over the last century caused widespread habitat loss and degradation. Establishment of protected areas aims to counteract the loss of habitats and to slow species extinctions. However, many protected areas also include high levels of habitat disturbance and conversion for uses such as cropland. Understanding where and why this occurs may realign conservation priorities and inform protected area policy in light of competing priorities such as food security. Here, we use our global synthesis cropland dataset to quantify cropland in protected areas globally and assess their relationship to conservation aims and socio-environmental context. We estimate that cropland occupies 1.4 million km or 6% of global protected area. Cropland occurs across all protected area management types, with 22% occurring in strictly protected areas. Cropland inside protected areas is more prevalent in countries with higher population density, lower income inequality, and with higher agricultural suitability of protected lands. While this phenomenon is dominant in midnorthern latitudes, areas of cropland in protected areas of the tropics and subtropics may present greater trade-offs due to higher levels of both biodiversity and food insecurity. Although area-based targets are prominent in biodiversity goal-setting, our results show that they can mask persistent anthropogenic land uses detrimental to native ecosystem conservation. To ensure the long-term efficacy of protected areas, post-2020 goal setting must link aims for biodiversity and human health and improve monitoring of conservation outcomes in cropland-impacted protected areas.
上个世纪，全球耕地扩张导致了广泛的栖息地丧失和退化。建立保护区旨在抵消栖息地的丧失，并减缓物种灭绝。然而，许多保护区也包括高水平的栖息地干扰和转换，用于耕种等用途。了解这种情况发生的地点和原因，可以调整保护重点，并根据粮食安全等竞争优先事项，为保护区政策提供信息。在这里，我们利用我们的全球综合耕地数据集来量化全球保护区内的耕地，并评估其与保护目标和社会环境背景的关系。我们估计，耕地占地全球保护区的 140 万平方千米，占全球保护区的 6%。耕地出现在所有保护区管理类型中，其中 22%出现在严格保护区内。在人口密度较高、收入不平等程度较低和保护区土地农业适宜性较高的国家，保护区内的耕地更为普遍。虽然这种现象在中高纬度地区占主导地位，但由于生物多样性和粮食不安全程度较高，保护区内耕地的热带和亚热带地区可能会出现更大的权衡。尽管基于面积的目标在生物多样性目标设定中很突出，但我们的结果表明，它们可能掩盖了对原生生态系统保护有害的持续人为土地利用。为了确保保护区的长期效力，2020 年后的目标设定必须将生物多样性和人类健康目标联系起来，并改善对受耕地影响的保护区的保护成果的监测。
